1. Technical Field
The present invention relates to a voltage equalizer that equalizes an inter-terminal voltage of each of a plurality of storage cells which are connected in series, a storage device in which the voltage equalizer is placed, and an operating machine in which the storage device is placed.
2. Description of the Related Art
A storage module, which is configured to have a plurality of storage cells connected in series, is placed in a hybrid type operating machine. Examples of the storage cell include an electric double layer capacitor, a lithium ion capacitor, and a lithium ion secondary battery. Voltage equalization circuits (balance circuits), which limit an inter-terminal voltage at or below a predetermined value, are respectively connected to the plurality of storage cells connected in series (related art).
The storage cell disclosed in the related art has a positive electrode terminal and a negative electrode terminal on an upper surface thereof. The plurality of storage cells are arranged to be lined up in a row. One substrate, on which a wiring pattern is formed, is arranged on the plurality of storage cells. The plurality of storage cells are connected in series by the wiring pattern formed on the substrate. The voltage equalization circuits are disposed on the substrate to correspond to the storage cells.
A discharge current that flows in the voltage equalization circuit increases as the inter-terminal voltage of the storage cells increases. Further, the discharge current increases as the temperature of the storage cells increases. In this manner, appropriate discharge corresponding to the temperature of the storage cells is possible, and the life of the storage cells can be extended.